Methods and apparatus for crimping yarns



Dec. 5, 1967 R. s. GILCHRIST ETAL 3,355,872 1 METHODS AND APPARATUS FOR CRIMPING YARNS Filed Dec. l5, 1964 Awww RQ United States Patent O 3,355,872 Martiens AND Arrnnsrns ron canarino YARN ABSTRACT F THE DHSCLGSURE A plurality of yarns are simultaneously crimped by intermittently moving them through separating means spaced apart in the direction of yarn travel, at least one of which is rotating, whereby the yarns are oppositely twisted at locations before and after the central area of the separating means. Heat may be applied to the yarns either differentially or non-diiferentially at the twisting locations.

rThis invention relates to methods for crimping yarns.

According to one aspect of the invention there is provided a method of crimping at least two yarns simultaneously in which lthe yarns are extended through three separating means spaced apart along the yarns and at least one of said separating means is rotated so that the stretches of the yarns on each side of the location oi the middle eparating means are twisted in opposite directions. When each said stretch has received its desired number of twists the twisting operation is arrested and then the yarns are traversed through the three separating means, the twists being maintained in the stretches of the yarns on opposite sides of said middle separating means.

During the said twisting operation the middle separating means may remain stationary and the end separating means be rotated in the same direction, either simultaneously or sequentially. The number of twists on each side Ot the middle separating means may be the same or different.

Alternatively, the middle separating means can be rotated to impart, or help impart, the opposite twists to said stretches of the yarns in this case the middle separating means will hereinafter be referred to as a or the twisting mechanism.

According to another aspect of the invention, there is provided a method of crimping two yarns simultaneously in which the yarns are arranged to extend between two yarn separating means and are subjected to a twisting operation at a location between the two said separating means so that the stretches of yarns between said location and the separating means are each twisted in opposite directions on opposite sides of said location which twisting operation is arrested after a predetermined nurnber of twists have been imparted to the yarn in each said stretch on each side of said location, whereatter the yarns are traversed through the yarn separating means, the twists being retained in the stretches of the yarns on opposite sides of said location. More than two yarns can be simultaneously crimped.

ICC

Preferably, the oppositely twisted stretches of yarns are heated on opposite sides of said location.

The lengths of said stretches of yarns on opposite sides of said location may differ. rthese lengths may be adjustable.

The yarns may be differentially heated on opposite sides of said location.

Each yarn can be monoor multi-filament and can include a thermoplastic component or be constituted of thermoplastic.

An apparatus for carrying out one aspect of the invention may comprise means for supporting two supply bobbins, two yarn separating means through which the yarns can pass, twisting mechanism disposed at a location be` tween the two yarn separating means and being capable of twisting the yarns together in opposite directions on opposite sides of the twisting mechanism, said twisting mechanism being adapted to permit the yarns to be drawn past it whilst maintaining the opposite twists in the yarns between it and the two yarn separating means, a driving transmission for the twisting mechanism embodying means for arresting the twisting mechanism, means for feeding the yarns through the apparatus, and means for setting the yarns.

The means for setting the yarns can comprise heating means on each side of the twisting mechanism.

The twisting mechanism may comprise a pin or the like which is inserted between the two yarns and extends in a direction transverse to the length oi the yarns and is mounted to rotate about an axis extending in the direction ofthe length of the yarns.

It will be appreciated with this arrangement that when the rotation of the pin is arrested and the two yarns are drawn past it, the number of twists in the two yarns on opposite sides of the pin will be preserved.

Alternatively, the twisting mechanism may comprise a structure on which are mounted either a number of rollers around which the yarns are respectively wound or a number of eyes or apertures through which the yarns are respectively threaded and means for rotating said structure about an axis parallel to the general direction of travel of the yarns.

Means may be provided for adjusting the position of the twisting mechanism relative to the two yarn separating means whereby the ratio of twists per inch in the yarns on opposite sides of the twisting mechanism may be varied.

Each yarn separating means may comprise two or more eyes or guides spaced apart transversely to the general direction of travel of the yarn and through which the yarns respectively pass.

In the case where two yarns are twisted together, the aforesaid feeding means may comprise two pairs of conical nip rollers each yarn passing between two of the nip rollers, one of which rollers in each pair has its axis arranged substantially at right angles to the twisted yarns prior to their separation, a structure disposed prior to said conical nip rollers and arranged to pivot freely about an axis transverse to the axes of rotation of said one roller in each pair, a first guide mounted on said structure and through which the twisted together yarns pass just before being separated, a pair of second guides mounted on said structure on the opposite side oi its pivotal axis to the first guide, the second guides being arranged so that a sepaa rated' yarnpasses through each prior to the separated yarns passing through said conical nip rollers. By these means the rate of separation of two crimped yarns may be automatically equalised since if one yarn is being separated at a greater rate than the other, the structure, by reason of unequal tension of the yarns, is swung in a direction to bring said one yarn onto a smaller part of the conical rollers which engage it.

The separated yarns may pass to separate take-up bobbins or may be wound on one and the same take-up bobbin.

It will be appreciated Ywith the above mechanism, or with other mechanisms for carrying out the invention, any of the following methods may be carried out.

The twisting of the yarns together may be carried out while the yarns are stationary, and after a predetermined number of twists have been imparted to the yarns in opposite senses on opposite sides of the twisting mechanism or the middle separating means, as the case may be, the twisting ceases and the yarns are then c-ontinuously drawn through the apparatus until the supply is exhausted- Alternatively, the initial twisting may be carried out while the yarns are travelling through the apparatus and when the required number of twists have built up in opposite senses on opposite sides of the twisting mechanism or the middle separating means, as the case may be, the twisting ceases and the travel of the yarn is continued until the supply is exhausted.

Alternatively, in either of the two methods just referred to above, instead of the twisting ceasing after the initial twisting together of yarns it may be carried out at a different rate or it may cease for a short period and then continue for another period and so on so that the crimp` ing effect along the yarns may be varied.

Similarly, the crimping effect along the yarn may be varied by cyclically moving the twisting mechanism or the middle separating means, as the case may be, between the two yarn end separating means. W According to yet another aspect of the present invention there is provided an apparatus for separating two yarns and feeding the separated yarns forward at equal speeds, said apparatus comprising a first guide through which they yarns pass prior to their separation, a pair of second guides through which the separated yarns pass, a member pivotal about an axis, said rst guide being mounted on said member n one side of its pivotal axis and said pair of second guides being mounted on said member on the other side of its pivotal axis, and two pairs of conical nip rollers, each pair of rollers being arranged adjacent one of said second guides so as to receive a separated yarn from that guide, the arrangement being such that when one of the separated yarns is being fed faster by its pair of conical rollers than the other separated yarn, then the reaction of the yarns before separation on the rst guide causes said member to pivot to move said second guide so that the faster moving separated yarn is moved to a smaller part of the conical rollers feeding it and the slower moving yarn moves to a larger part of the conical rollers feeding it.

By way of example, embodiments of the invention will now be described with reference to the accompanying diagrammatic drawing drawing which is a schematic plan view of an apparatus with part of said twisting mechanism shown in section.

Two yarns 10, 11 (for example, 40 denier 13 filament nylon 66 yarns) to be processed are drawn oif supply bobbins 12 and 13 mounted Yon a fixed part of the apparatus. The yarns pass through two eyes 14, 15, respectively, also mounted en a fixed part of the apparatus. The yarns are wound respectively around two rollers 16, 17 rotatably attached to a bar 18 which extends across and is mounted in an externally toothed gear ring 19 which meshes with and is supported by a plurality of idler gear wheels (not shown) so as to be rotatable about an axis extending in the general direction 4 of the yarn. The gear ring 19, and thereby the bar 18', is rotatable by a motor 20 through a variable speed transmission 21 and a pinion 8 mounted on a shaft 9. The transmission 21 may embody a clutch mechanism (not shown) whereby rotation of the gear ring 19 and bar 13 may be stopped or started.

The two yarns are oppositely twisted at 22 and 23 on opposite sides of the twisting mechanism and these oppositely twisted stretches of the yarns travel over two heaters 24, 25 which may be at the same or different temperatures. The twisted stretch 23 of the yarns then passes through an eye or guide 26 mounted at the end of a bar 27 freely pivoted at 27a to a fixed part of the apparatus. The two now crimped yarns 10 and 11 separate at or adjacent the guide 26 and pass respectively through two eyes 2S and 29, mounted on a fixed part of the apparatus, and thence through two further eyes 31, 32 mounted on the arms of a V-shapedV member 30 secured firmly to the other end of the bar 27 by a screw 33. The yarns then pass between two pairs of conical feed rollers 34, 35 and 36, 37 respectively. The rollers 34 and 36 are mounted on a shaft 38 driven by a motor 39 through a change speed gear 40 embodying clutch means for engaging and disengaging the drive. The two yarns pass from the two pairs of feed rollers via traversing guides onto take-up spools 41, 42 mounted on a shaft 43 driven through a suitable transmission 44 from the motor 39.

The guide 26, bar 27, arms 30 and conical feed rollers 34, 35 and 36, 37 together forma compensating mechanism to enable the two yarns 10, 11 to be separated at the same rate and the separated yarns to be fed to the take-up packages 41, 42 at the same speed. The functioning of this compensating mechanism will now be described. Idcally the two yarns should separate immediately after passing through the guide 26. However, suppose the rollers 36, 37 are drawing the yarnv 11 from the guide 26 at a faster speed than the rollers 34, 35 are so drawing the yarn 10: the point of separation of the yarns 10, 11 will then pass beyond the guide 26 and will start to move towards the eye 29. Before this point of separation reaches the eyel 29', the stretch 23 of twisted yarn now extending through the guide 26 will exert a pull on the guide 26 in a direction generally towards the top of the accompanying drawing and this will cause the bar 27 to turn about its pivot 27a clockwise so that the guide 26 moves towards the top of the drawing, and the eyes 31, 32 on the arms 30 move towards the bottom of the drawing. The movement of the eye 32 causes the yarn 11 to move towards the narrower ends of theV rollers 36, 37 and so be drawn at a slower speed by these rollers; whereas the simultaneous ymovement of the eye 31 causes the yarn 10 to move towards the larger ends of the rollers 34, 35 and so be drawn at a faster speed by the rollers 34, 35. The clockwise movement of the bar 27, and arms 30, about the pivot 27a continues until the point of separation of the two yarns 10, 11 starts to move back towards the guide 26 and eventually the bar 27 will come to rest in a 'datum position such that the two yarns 10, 11 are being drawn at the same speed by the rollers 34, 35 and 36, 37. In this datum position, the bar 27 should be midway between the eyes 28, 29 as shown in the drawing. If it is not, then the screw 33 can be loosened and the position of the arms 30 relative to the bar 27 adjusted until the bar 27 reaches the desired datum position, the screw 33 then being tightened to lock the arms 30 relative to the bar 27. Should the separated yarn 10 start running faster than the separated yarn 11, with the consequence that theY point of separation of the yarns starts moving from the guide 26 towards the eye 28, then the bar 27 will move anti-clockwise until the speeds of the two separate yarns are compensated and the point of separation of the two yarns will return towards the guide 26. It will be noticed that the guide 26 is a greater distance from the pivot 27a than the eyes 31, 32 and this makes the compensating mechanism more sensitive: preferably the guide 26 is at least twice the distance from the pivot 27a as the eyes 31, 32.

When the apparatus is to be started up, the two yarns 10, 11 are drawn by hand from the bobbins 12, 13, through the eyes 14, 15, then each yarn is wound around its roller 16 or 17, and then the two yarns are passed through the guide 26 and on through the other eyes etc. to the spools 41, 42. The motor 20 is then caused to rotate the gear ring 19 a predetermined number of revolutions to insert a predetermined number of twists in the oppositely twisted stretches 22, 23 on each side of the twisting mechanism. This initial twisting operation is then arrested and the drive to the feed rollers 34, 36 and to the take-up packages 41, 42 started and the two yarns commence travelling through the apparatus from the supply bobbins 12, 13 to the take-up packages 41, 42. Because the gear ring 19 isnow stationary, the twisted stretches 22, 23 will remain on each side of the gear ring 19. Thus with the heaters 24, 25 in operation, the yarns as they travel through the apparatus are first twisted about each other in Vone direction in the stretch 22 and this twist is set in the two yarnsby the heater 24. As the yarns are separated for the rst time by the rollers 16, 17 this set twist is de-twisted so producing a torsionally strained yarn similar to a conventionally false twisted yarn. The yarns are then twisted about each other in the opposite direction in the stretch 23 where they are set in the voppositely twisted state by the heater 25 before being separated by the eyes 28, 29- this second phase of operation on the already torsionally strained yarns similating a false twist operation in the opposite direction.

The properties `of the iinal yarn passing to the packages 41, 42 will depend upon several factors, particularly the degree of heating imparted by the respective heaters 24 and 25: the iinal yarn may be arranged to have a residual torque in either the S or Z direction. However, it will be appreciated that by correct selection or adjustment of the heaters 24, 25 and correct adjustment of the axial position of the twisting mechanism relative to the two end separating means, the crimped yarns would onto the spools 41, 42 can be substantially non-torque crimped yarns: an advantage of the present invention is that such non-torque crimped yarns can be produced by twisting the yarns twice but without the use of conventional false twisting heads. ln fact, after the twisting mechanism has initially inserted the predetermined number of opposite twists in the stretches 22 and 23 of the yarns, the yarns can be continuously crimped as they pass from the bobbins 12, 13 to the spools 41, 42 without further rotation of the twisting mechanism 16, 17, 1S, 19 which remains arrested.

If desired, the gear ring 19 and -bar 1d andthe driving mechanism therefor may be arranged to be axially movable in relation to the two pairs of eyes 14, and 28, 29, respectively, so that the relative lengths of the twisted stretches 22 and 23 can be Varied to a considerable extent if desired.

In a modification of the illustrated embodiment the two end separating means, that is the two eyes 14, 15 on the one hand and the two eyes 2S, 29 on the other hand, can be movable towards and away from the twisting mechanism 16, 17, 18, 19 in order to adjust the lengths of the oppositely twisted stretches 22 and 23 of yarns in order to control the quality and character of the crimp in the finally crimped yarns wound onto the spools 41, 42.

in a further modication, the rollers 16, 17 may be connected to driving means for rotating them about their own axes in order to facilitate the traversing of the yarns through the apparatus.

Depending upon the yarn being crimped and the properties required in the crimped yarn, the eyes 14, 15 may each be replaced by a yarn tensioning device such as, for example, a gate tensioner or a hysteresis tensioning disc.

Alternatively, or in addition, each yarn may pass through a pair of positive feed rollers before being advanced to the twisted stretch 22: with this arrangement the yarn can be overfed to the twisted stretch 22 i desired.

The bar 18 and the rollers 16, 17 may be replaced by any suitable mechanism capable of imparting the initial twist to the stretches of yarn to either side of it, and then of separating the yarns as they pass from one side of it to the other.

It will be appreciated that with suitable modifications, three, four or even more yarns can be twisted about each other in oppositely twisted stretches and simultaneously processed.

What we claim is:

1. A method of crimping at least two lengths of yarn comprising the steps of: (a) combining the lengths of yarn to form a number of twists in each length; (b) setting the combined yarns to impart a crimp to each length; (c) separating the lengths of yarn aiter said setting step; (d) combining the lengths of yarn a second time to again form a number of twists in each length; (e) setting the yarns when they are combined the second time; and (f) separating the yarns after said second setting step.

2. The method in accordance with claim 1 wherein said first combining step comprises the steps of: (a) feeding the yarns axially; and (b) twisting the yarns about each other.

3. The method in accordance with claim 2 including the step of arresting said twisting step when a number of twists are formed, said feeding step continuing thereafter.

4. The method in accordance with claim 2 including the step of varying the crimping effect on the yarns.

S. The method in accordance with claim 4 wherein said step of varying the crimping effect includes the step of changing the rate of twist after a number of twists have been formed.

6. The method in accordance with claim 4 wherein said step of varying the crimping effect includes the steps of rst arresting said twisting step and then resuming said twisting step, both said last-mentioned steps being performed while said feeding step is being performed.

7. The method in accordance with claim 3 wherein sai-d twisting step is performed when said yarns are separated the iirst time.

8. The method in accordance with claim 7 including the step of feeding each yarn about an axis that is at an angle to the direction of feed during the time the yarns are separated, said last-mentioned feeding step occurring intermediate said first setting step and said second combining step.

9. The method in accordance with claim 1 wherein at least one of said setting steps comprises the step of applying heat to the yarns.

1t). The method in accordance with claim 1 wherein both said setting steps comprise the steps of applying heat to the yarns.

11. The method in accordance with claim 10 wherein the same degree of heat is applied in both setting steps.

12. The method in accordance with claim 1t) wherein different degrees of heat are applied in each setting step.

13. The method in accordance with claim 1 wherein said combining steps comprise the steps of twisting the yarns about each other in the same angular direction.

14. The method in accordance with claim 1 wherein said combining steps comprise the steps of twisting the yarns about each other in one angular direction at said first combining step and then twisting the yarns about each other in the opposite angular direction at said second combining step.

15. The method in accordance with claim 1 wherein said first separating step includes the step of changing the number of twists in the combined yarns.

16. The method in accordance with claim 1 including the steps of forming the same number of twists at each said combining step.

17. The method in accordance with claim 1 including the steps of forming a different number of twists at each said combining step.

18. The method in` accordance with` claim 1 wherein said second separating step includes the step of removing the twist imparted to the yarns during said first-setting step;

19. The method in accordance With claim 18 wherein said second combining step comprises forming the desired number of twists in the yarns subsequent to the step of removing the twists, said reformed twists being in an opposite angular direction to the twists that were removed.

References Cited UNITED STATES PATENTS Burleson 57157 Finlayson 57-157 X Klein 57`34 Carruthers 57-34' Comer et a1'. 57-157 Carruthers 57-34 X Carruthers 57-3'4 Kunzle 57-34 Kunzle et al. 57-34 FRANK I. COHEN, Primary Examiner.

15 D. E. WATKINS, Assistant Examiner. 

1. A METHOD OF CRIMPING AT LEAST TWO LENGTHS OF YARN COMPRISING THE STEPS OF: (A) COMBINING THE LENGTHS OF YARN TO FORM A NUMBER OF TWISTS IN EACH LENGTH; (B) SETTING THE COMBINED YARNS TO IMPART A CRIMP TO EACH LENGTH; (C) SEPARATING THE LENGTHS OF YARN AFTER SAID SETTING STEP; (D) COMBINING THE LENGTHS OF YARN A SECOND TIME TO AGAIN FORM A NUMBER OF TWISTS IN EACH LENGTH; (E) SETTING THE YARNS WHEN THEY ARE COMBINED THE SECOND TIME; AND (F) SEPARATING THE YARNS AFTER SAID SECOND SETTING STEP. 